Centrifugal fluid pump



Dec. 5, 1967 i F. E. ULLERY 3,356,033

CENTRIFUGAL FLUID PUMP Filed Oct. 22, 1965 FRED E.LJL .I ERY INVENTOR.

ATTORNEYS United States Patent O 3,356,033 CENTRIFUGAL FLUID PUMP FredE. Ullery, Detroit, Mich, assignor to Ford Motor Company, Dearborn, Micha corporation of Delaware Filed Oct. 22, 1965, Ser. No. 500,534 6(Ilaims. (Cl. 103-96) ABSTRACT OF THE DISCLOSURE A centrifugal pump hasa toroidal shaped cavity that is split in two along a plane normal tothe axis of rotation. One-half of the torus contains a bladed rotor, theother half being bladeless, but containing a block seal or abutment witha fluid inlet and outlet to the torus chamber located on opposite sidesof the abutment. The abutment in general is wider circumferentially thanthe space between two adjacent rotor blades, to seal and trap fluid inthe space as the blades pass overthe abutment. However, a portion of theouter part of the abutment is cut away and angled towards the inlet todirect a portion of the trapped fluid toward the inlet in a manner toimpart energy to it.

This invention relates in general to a fluid pump, and more particularlyto one of the centrifugal type.

The prior known Centrifugal pumps of the type in mind generally containa toroidal-shaped cavity that is split in two along a plane normal tothe axis of rotation. One-half of the torus contains blades and isrotatable, the other half being bladeless and held stationary. Thestationary or stator half usually has a single fluid inlet and outletlocated on opposite sides of a block seal or fluid abutment. The blockseal normally is of a circumferential width slightly greater than thedistance between rotor blades and has a radial surface that sealinglycooperates with the peripheral edges of the blades. This prevents thefluid contained in the stator half of the torus from flowing between theoutlet and inlet when the blades pass over the abutment.

When the rotor portion is driven, fluid is drawn through the inlet intothe rotor blade cavities, and, by centrifugal force, is thrown outwardlyin the general direction of movement of the blades into the stator toruscavity. Due to the shape of the stator torus wall, the fluid isredirected back into the rotor blade cavities Where additional energy isimparted to it. The repetition of this cycle several times perrevolution establishes a helical spiral motion to the fluid during itscircumferential progression around the torus. The fluid is then expelledout through the outlet.

In general, most of the prior art constructions of this type haveseveral disadvantages. One is that the outlet generally is so disposedadjacent the block seal that the direction of motion of the dischargingfluid changes abruptly. This decreases the fluid energy, increases thepressure, and in eifect causes the fluid to pile up at the outlet, thusreducing the output of the pump.

Another equally, if not more important, disadvantage is the largeclearance volume or size of the cavities between rotor blades in whichconsiderable fluid energy is trapped or retained and carried over to thelow pressure inlet side of the pump as the blades pass over the abutmentseal surface.

Since the operational performance of a pump of this type fundamentallyis dependent upon the fluid movement having a whirl component that isinduced and maintained by the rotor blades, a further disadvantage ofthe prior art devices is the general lack of suitable means toeffectively start the whirl of the fluid in the vicinity of the inlet.

The invention eliminates the above disadvantages by providing acentrifugal pump construction in which; the fluid outlet port is solocated and disposed near the outer periphery of the stator shell thatthe fluid is discharged substantially without a change in the directionof movement of the fluid; the fluid abutment or block seal is formed todirect the fluid to the outlet port near the outer periphery of thefluid path; the abutment is constructed to recirculate a portion of thenormally trapped rotor blade cavity fluid toward the inlet side of thepump to aid the inducement of a Whirl motion to the incoming fluid; and,a whirl inducing blade is provided adjacent the pump inlet so that fluidwill enter the rotor blade cavities in an eflicient manner.

One of the principal objects of the invention, therefore, is to improvethe performance eifectiveness of a centrifugal pump of the general typedescribed.

A further object of the invention is to provide a centrifugal pump witha fluid outlet cooperatingly located with respect to the fluid abutmentand so disposed as to effect an eflicient discharge of the fluid with aminimum change in direction of motion of the fluid being discharged.

A further object of the invention is to provide a centrifugal pump witha fluid abutment or block seal constructed to provide a fluid passageprogressively increasing in cross-sectional area towards the fluid inletwhereby fluid normally trapped in the cavity between rotor blades asthey pass over the block seal will be recirculated to the pump inlet andinduce a whirl component to the entering fluid.

A still further object of the invention is to provide a centrifugal pumpof the type described above in which the abutment passage consists of acurved ramp surface connected to the fluid inlet.

Another object of the invention is to provide a whirl inducing bladeadjacent the fluid inlet so that the incoming fluid will enter the rotorblade cavities in a favorable direction.

It is also an object of the invention to provide a centrifugal pump ofthe type described in which the fluid inlet is formed as a part of theblock seal or fluid abutment, and is alternately located in the radialface sealing surface for low volume and high velocity pump operation, oris obliquely disposed through the ramp for higher volume operation.

Other objects, features and advantages of the invention will becomeapparent upon reference to the succeeding, detailed description thereof,and to the drawings illustrating the preferred embodiments thereof;wherein,

FIGURE 1 is a cross-sectional view of a centrifugal pump embodying theinvention;

FIGURE 2 is an enlarged cross-sectional view taken on a plane indicatedby and viewed in the direction of the arrows 22 of FIGURE 1;

FIGURE 3 is a reduced cross-sectional view taken on a plane indicated byand viewed in the direction of the arrows 3-3 of FIGURE 2;

FIGURE 4 is a cross-sectional view taken on a plane indicated by andviewed in the direction of the arrows 4-4 of FIGURE 1;

FIGURE 5 is an enlarged view of a detail of FIGURE 4; and,

FIGURE 6 is rear-elevational view of FIGURE 1 viewed from right to left.

FIGURE 1, which is essentially to scale, shows a centrifugal-type pumpconsisting essentially of annular rotatable and stationary members 12and 14 that are nested in a fluid sealing manner. Rotor member 12 ismade up of three portions that are bolted or otherwise secured together:a driving pulley 16, a flanged hub or sleeve 18, and a radiallyextending torus shell member 2%). Sleeve 18 is journaled on the enlargedend 22 of a shaft 24 that extends axially to the right for support ofthe stator shell 26. The stator shell is essentially a thick plate ordisc, and is axially slidably mounted on a sleeve 28. The sleeve isslidable axially on shaft 24, and non-rotatably pinned to it, as shown.Stator 14 is biased toward rotor 12 by a spring 30 that abuts the statorhub at one end, as shown, and is seated at its opposite end against theflange of a retainer 32. The retainer is axially adjustably secured toshaft 24.

The construction described permits axial movement of stator shell 26relative to rotor shell 2t) when the internal pressure of the pumpexceeds a predetermined level, to prevent a pressure buildup beyond auseable level, and thereby prevent further increase in the enginehorsepower loss.

The rotor and stator shells 20 and 26 are formed respectively withsemi-toroidal-shaped cavities 34 and 36. The cavities face each otherand are substantially contiguous so as to form a toroidal chamber 38 forthe circurnferential flow of a fluid such as air through it. As bestseen in FIGURES 1, 2 and 3, rotor cavity 34 has a number ofcircumferentially spaced blades 40 that extend in the general directionof rotation of the rotor and are of an axial width to extend to theinner radial face 42 of rotor disc 20.

Stator cavity 36, on the other hand, is void of blades. As best seen inFIGURE 4, the stator cavity is provided in general with a single fluidabutment or block seal 44 that circumferentially separates a fluid inletport 46 from a fluid outlet port 48.

The fluid inlet is obliquely positioned through the abutment 44, for apurpose to be described. The fluid outlet 48 is obliquely disposed nearthe outer periphery of the fluid path so that it is substantially inline with the direction of flow at this point. This provides a minimumchange in the direction of movement of the fluid as it is discharged,and, therefore, retains most of the fluid energy developed. The axialface 50 of the abutment 44 at this point is suitably curved to directthe fluid into the discharge port.

The block seal 44 is secured to the stator in any suitable manner. Theseal is of an axial thickness to fill up the stator cavity 36 at thispoint, and has an inner radial or face surface 52 in sealingrelationship to the tips of rotor blades 40.

In the prior art centrifugal pump constructions, as stated previously,the abtument or block seal is generally solid or continuous throughoutits width and length, and is of a circumferential width wherein even thenorrowest portion is slightly wider than the distance between rotorblades. Thus, in the prior art constructions, considerable velocityenergy is lost by the trapping of a large volume of fluid in the cavitybetween the rotor blades as it passes over the abutment seal surface.This invention makes use of a portion of this velocity energy to inducea whirl component to the incoming fluid, thereby increasing theefliciency of the pump.

More specifically, the radially inner portion 54 of abutment sealsurface 52 is circumferentially wider than the distance rotor blades,and is considerably wider than the radially outer portion 56, as seen inFIGURE 5. The narrow outer portion is formed by providing an arcuatelycurved groove that defines an arcuate ramp or inclined surface 58. Theramp together with the surrounding parts of the abutment and statorcavity forms a passage 60 that gradually increases in cross-sectionalarea towards the inlet side of the pump. This permits a portion of thedischarge air that is normally trapped in the cavity between rotorblades 40 to pass over the narrow ridge portion 56 of the block seal anddown the ramp 58 to be recirculated back to the inlet 46. The rampcurvature is such as to induce a whirl component to the fluid flowingdown the ramp and to the fluid admitted through the inlet 46. Theincoming fluid, therefore, now enters the cavity between rotor blades 40on the low pressure side of the pump in a more efficient manner and in afavorable direction so that a greater output can be obtained.

The obliquely disposed inlet port 46 further aids in the development ofa whirl component to the incoming air by directing the incoming fluid ina path substantially parallel to the direction of flow of the fluid downthe ramp passage. This is an advantageous location for the inlet toprovide high volume, low pressure pump operation.

Alternatively, if low volume, high pressure operation is desired, theinlet could be located in the face of the abutment or block seal surface52. In this latter location, the outer portion of the fluid normallytrapped between the rotor blade cavities would flow down the ramppassage 60, with any loss in the volume of fluid in the rotor bladecavity being made up from the inlet in the face of the block seal. Thetwo volumes of air then combine at the inlet side of the block seal, theramp passage air inducing a whirl component to the incoming air.

To further aid in inducing a whirl component to the incoming air, awhirl inducing blade member 64 is fixed to the stator shell 26 andpositioned slightly downstream of the fluid inlet 46. It isappropriately curved in cross-sectional shape to provide the desiredamount of whirl to afford the most efiicient entry into the rotor bladecavities. While it is described as being fixed, it will be clear that itcould be pivotally mounted and adjusted by any suitable means, automaticor manual, without departing from the scope of the invention.

In operation, rotation of rotor 12 by any suitable means, such as, forexample, a fan belt driven by the crankshaft of an internal combustionengine (not shown), initially induces a flow of incoming fluid through,say, the obliquely disposed inlet 46 to fill up the cavities betweenrotor blades 40. Because of the rotation and direction of inclination ofthe rotor blades, the air is thrown forwardly and outwardly bycentrifugal force from the roots to the tips of the blades and into thestator cavity. The dish-like cross-sectional shape of the stator wallthen guides the fluid back into the rotor blade cavities where it hasadditional energy imparted to it.

The repeated forward ejection and return of the fluid establishes ahelical spiral path to the fluid during its circumferential progressionaround the toroidal cavity. The fluid velocity thus progressivelyincreases, and as it approaches the outlet port 48, the fluid is flowingin a helical spiral path, as indicated by arrows 66 in FIGURE 4. Sinceoutlet port 48 is obliquely positioned so as to be substantially alignedwith the fluid entering it, there is a minimum of change to thedirection of motion of the fluid as it passes through the port, and,therefore, substantially little loss in velocity energy. The curvatureof the face 50 of the abutment at this point aids in directing the fluidinto the outlet. The discharging fluid will then enter an outletmanifold 68 and be diffused whereby the velocity energy is converted topressure.

At this point, the rotor blades begin to pass over the radial sealsurface 52 of the block seal or abutment 44. The radially outer portionof the discharge air that is normally trapped in the cavities betweenrotor blades now passes over the narrow abutment ridge 56 andimmediately is forced into the diverging passage 60. The arcuate wallsof the passage then guide the fluid in a direction past the obliquelydisposed inlet 46 to provide a whirl component to the entering air. Thiswhirl component is additionally fortified by the flow of the air pastthe whirl blade 64. As a result, the velocity energy of the fluidpassing down the ramp is imparted to the incoming air and in a directionsubstantially tangent to the ultimate helical spiral path that isestablished as it travels around the torus from inlet 46 to outlet 48.

It will be clear that suitable shut-off or fluid-blocking means,automatically or manually operated, can be provided to alternatelychange the outlet from the obliquely inclined port 46 to the flush port62 in the face seal surface 52, without departing from the scope of theinvention.

It will also be clear that while the obliquely disposed outlet and inletports are shown as being substantially elliptical in cross section, thatother suitable shapes could be provided without departing from the scopeof the invention.

From the foregoing, therefore, it will be seen that the inventionprovides a centrifugal pump having a number of features that providebetter operating efficiency for a pump of this type; namely, a fluidoutlet port that is obliquely disposed so as to be substantially in linewith the direction of motion of the discharging fluid to thereby reducelosses through the port; a block seal or abutment that has a curvatureto aid the discharge of fluid through the outlet port; a block seal thatis recessed to provide a ramp surface of an area progressivelyincreasing towards the fluid inlet to utilize some of the fluid energynormally trapped in the cavity between rotor blades to induce a whirlcomponent to the incoming fluid; alternate positions for the fluid inletport for varying the pump operation desired; and, finally the use of awhirl inducing blade to aid in the inducement of a whirl component tothe incoming fluid.

While the invention has been described preferably for use as an airpump, it will be clear that it would be suitable to pump liquids andother media as Well.

While the invention has been described and shown in its preferredembodiment, it will be clear to those skilled in the arts to which theinvention pertains that many changes and modifications may be madethereto without departing from the scope of the invention.

I claim:

1. A fluid pump of the centrifugal type comprising axially alignedannular stationary and rotatable members in substantially contiguousrelationship each having a semitoroidal-shaped fluid cavity definedtherein, said cavities facing each other to together define atoroidal-shaped cavity for the flow of fluid therearound, said rotatablemember cavity having circumferentially space blades mounted therein andextending across the axial width thereof, said stationary member havinga fluid inlet and an outlet circumferentially separated by a fluid flowabutment blocking communication in the normal flow direction betweensaid inlet and outlet through said stationary member cavity, saidabutment having a radial seal surface in fluid sealing relationship withsaid rotor blades, the radially inner circumferential portion of saidabutment surface being longer than the circumferential space between apair of rotor blades to trap fluid in said space as said pair of bladesrotates past said surface, the radially outer portion of said abutmentsurface being circumferentially shorter than said inner portion and thespaces between pairs of blades whereby a portion of the fluid trapped ineach of said rotor blade spaces as it passes said abutment is forcedtowards said inlet prior to the communication of all of the space withsaid inlet.

2. A fluid pump as in claim 1, wherein said shorter outer abutmentportion defines a ramp inclined downwardly towards said inlet from saidsurface to provide a passage that progressively increases incross-sectional area towards said inlet.

3. A fluid pump as in claim 2, including a fluid whirl inducing guideblade positioned adjacent the path of flow of fluid through saidpassage.

4. A fluid pump as in claim 1, wherein said shorter outer abutmentportion defines an area between said outer abutment portion and saidinlet that increases in crosssectional area towards said inlet.

5. A fluid pump as in claim 1, wherein said shorter outer abutmentportion defines a fluid guide passage with a cross-sectional areaincreasing in the direction of said inlet.

6. A fluid pump as in claim 5, wherein said passage has a curvatureinducing a whirl motion to fluid entering said stationary member cavitythrough said inlet.

References Cited UNITED STATES PATENTS 1,619,286 3/1927 Burks 103962,396,319 3/1946 Edwards et al 103-96 2,923,246 2/1960 Wright 103-963,095,820 7/1963 Sanborn et a1. 10396 3,252,421 5/1966 Luhrnann 10396FOREIGN PATENTS 902,074 1/ 1954 Germany.

13,925 9/ 1925 Neitherlands.

DONLEY I. STOCKING, Primary Examiner. HENRY F. RADUAZO, Examiner.

1. A FLUID OF THE CENTRIFUGAL TYPE COMPRISING AXIALLY ALIGNED ANNULARSTATIONARY AND ROTATABLE MEMBERS IN SUBSTANTIALLY CONTIGUOUSRELATIONSHIP EACH HAVING A SEMITOROIDAL-SHAPED FLUID CAVITY DEFINEDTHEREIN, SAID CAVITIES FACING EACH OTHER TO TOGETHER DEFINE ATOROIDAL-SHAPED CAVITY FOR THE FLOW OF FLUID THEREAROUND, SAID ROTATABLEMEMBER CAVITY HAVING CIRCUMFERENTIALLY SPACE BLADES MOUNTED THEREIN ANDEXTENDING ACROS THE AXIAL WIDTH THEREOF, SAID STATIONARY MEMBER HAVING AFLUID INLET AND AN OUTLET CIRCUMFERENTIALLY SEPARATED BY A FLUID FLOWABUTMENT BLOCKING COMMUNICATION IN THE NORMAL FLOW DIRECTION BETWEENSAID INLET AND OUTLET THROUGH SAID STATIONARY MEMBER CAVITY, SAIDABUTMENT HAVING A RADIAL SEAL SURFACE IN FLUID SEALING RELATIONSHIP WITHSAID ROTOR BLADES, THE RADIALLY INNER CIRCUMFERENTIAL PORTION OF SAIDABUTMENT SURFACE BEING LONGER THAN THE CIRCUMFERENTIAL SPACE BETWEEN APAIR OF ROTOR BLADES TO TRAP FLUID IN SAID SPACE AS SAID PAIR OF BLADESROTATES PAST SAID SURFACE, THE RADIALLY OUTER PORTION OF SAID ABUTMENTSURFACE BEING CIRCUMFERENTIALLY SHORTER THAN SAID INNER PORTION AND THESPACES BETWEEN PAIRS OF BLADES WHEREBY A PORTION OF THE FLUID TRAPPED INEACH OF SAID ROTOR BLADE SPACES AS IT PASSES SAID ABUTMENT IS FORCEDTOWARDS SAID INLET PRIOR TO THE COMMUNICATION OF ALL OF THE SPACE WITHSAID INLET.